The present invention relates to an improved method for producing a gap spacer for magnetic heads, and more particularly relates to a method which produces a non-magnetic gap spacer having a controlled and uniform thickness.
Magnetic heads used in electric and electronic appliances are generally made up of a ring-shaped core and a coil wound around the core. In the case of a stereo set, for example, a pair of heads carried by a core holder are encased within a shield housing. The ring-shaped core has a small radial gap defined by a pair of mating ends and a gap spacer is inserted in the gap in tight contact with the mating ends.
In the production of a permalloy or sendust head, a non-magnetic wafer of a several micron thickness is clamped between a pair of mating ends after polishing and lapping of the latter to provide a gap spacer. In the case of a ferrite head, a thin glass plate sandwiched by a pair of ferrite blocks is heated at a temperature of several hundred degrees for formation of a gap spacer via chemical bonding between the glass and ferrite materials.
Conventionally, production of the non-magnetic wafer and the thin glass plate was carried out by rolling to a raw material. In practice, however, it is very difficult with the conventionally used materials to successfully produce a wafer or the thin plate having a uniform thickness of 1.5 m by means of rolling. This difficulty in producing plates by rolling sharply reduced materials which could successfully be used.